I actually tried the code there before I put it in init.php and the widget didn’t even show up, but I tried again as we’ve tweaked the code. Removed it from init.php and moved to the functions box of Custom Code area. The widget is gone again from the Widgets page.

Anita’s work is spot-on, but it seem you still have a problem. The code from Brad will work (I’ve used it before for a slider) and it works as you’ve modified it in a cut-and-paste test on a local install to setup your desired widget.

There must be some small conflict being overlooked.

I’ve screen-capped my result with Genesis action hooks showing if it helps: